Automatic control synchronizer



May 25, 1948. R. E. RUTH ET AL 2,442,149

' AUTOMATIC CONTROL SYNCHRONIZER Filed March 14, 1945 4 Sheets-Sheet 1 l I l l l R I l I J a I Elmo/M044 Harvey y 25, 1943- R. E. RUTH El AL AUTOMATIC CONTROL SYNCHRONIZER 4 Sheets-Sheet 2 Filed March 14, 1945 May 25, 1948p R. E. RUTH ET AL I 2,442,149

I I AUTOMATIC CONTROL SYNCHRONIZER 7 Filed Marchl l, 1945 4 Sheets-Sheet 3 5 45. 11:1; l 5524 277/ 45 /6 RUZJ YZzrV. ay

/ 6'1 WWZQW y 1948. R. E. RUTH ET AL 2,442,149

AUTOMATIC CONTROL SYNCHRONIZER Filed March 14, 1945 4 Sheets-Sheet 4 6 7 2M WJQWW Patented May 25, 1948 UNITED STATES PATENT OFFICE AUTOMATIC/CONTROL 'SYNGHRONIZER.

Raymond E. Rut-hand Robert L. Harvey,

. Odessa/[ext ApplicationlMarchl l, 1945, Serial No. 582,698

11 Claims. 1.

This invention relates generally to automatic control. systems in which meansresponsive. to the temperature of. aheatl source is employedto adjust. the temperature thereof. to a. desiredvalue automatically, the invention being employed. to.

advantage, for examplain connection Withithe operation of furnaces,.ovens', or like heat devices Whereinautomatic temperature control of: the devices is desired;

More specifically, the present invention contemplates the provision of means responsiveto the temperature of an internal combustion'engine for automatically adjusting the temperature thereof to a. value indicative of. a desired speed; of the engine, it. being well known that the speed ofaninternalcombustion engine is proportional to the temperature thereof and that the temperature,

therefore, when calibrated, gives a convenient indication of'the speed of the engine.

The present invention is particularlywell suited for synchronizing the. speeds. of a. plurality of internal'combustion engines which are employed topull' the same ordifferent loads'at the same speed, and for this purpose a control system of the present invention is. employed with each of the engines. The nicety of .this arrangementin synchronizing the speedsof' two or more engines pulling the same load is readily appreciated for thereason that a direct reading of the R. P. M. of the engines givesno indication that the engines are sharing equally the load carried thereby, as

one engine operatingl'at. the desired speed may pull substantially the entire loadwhile the other engines merely idle along therewith, thereby over loading saidone of the engines, which overload ing increases the fuel consumption of the engine and causes premature wearing of the parts thereof. However, the individual temperatures of the several engines indicate the amount of power eachengine would. deliver to theloadiand the operating speed thereof if each of the" engines were to pull theload alone.

Accordingly in the. preferred arrangement of the present invention, means responsive to the temperature. of an internal combustion engine" and adapted to generate currents or voltages variably in accordance with the temperature thereofis employed to actuate a plurality of elec fro-responsive means, in turn, are arranged to cause operation of an. el'ectromotive means for adiustingthe engine. throttle in 51101119; manner as to efiect. an adjustment thereof adapted to produce. an. engine temperature. corresponding to the: desired. speed thereof, the. foregoing. operation being: accomplished. without need for the.

2'. usual rods, shafts, turnbuckles, cams, han wheels and'other parts which make up'the. conventional throttle control. unitsemployed; on large engine installations, and in the specific manner more clearly to appear hereinafter.

Still other objects, advantages and features of the invention not specifically set forth herein above are those .which. Willi be specifically described in the following description and those implied. from or inherent in the novel combination Figure. 2A illustrates a. motor control circuit suitable for use. with. the electrical. system of Figuresl and IA;

Figure 3 is'an. enlarged sectional view of the throttle control'unit. shown in Figure 1;

Figure 4' is a somewhat more detailed view-i1'- lustrating the structure of the thermocouple and certain of the electromagnets associated there with in Figural;

Figure. 4A illustrates an alternate constructionfor. they relaysshown. in Figure 4;

Figure 5 is a diagrammatic viewiof. an alternate circuit arrangement for. energizing the electromagnets shown controlled by the thermocouple in Figures 1 and 1A; and

Figure 6 isa diagrammatic viewof another alternate circuitarrangement for controlling the energization of the electromagnets shown con trolledby the thermocouple in Figures land 1A.

Referring now to the drawings for a more complete understanding of. the invention and more particularly to Figures 1. through 4 thereof, the numeral Id generally designates a throttle control unit having a link orrarm which is adapted to be connected to the throttle of an internal combustion engine in a manner to control the flow of, fuelthereto in accordance with. various adjustments of the arm which, forthis'purpose, is pivotally connectedtoa rotatable disc i2. Disc I2 is mountedlf'or rotation about a short shaft I 3 which is threadedly securedto a stationary disc M withwhi'chdi'sc. i2 is preferablymountd in registered andslidable engagement at i5; Disc I2 has. aflange IEi-to which a disc I! is removably secured in. registered engagement therewith as by suitable screws I8, disc I! being provided with a central opening for permitting extension of shaft i3 therethrough whereby discs 12 and I4 may be secured against axial movement relative to each other as by a nut I9.

Discs l2 and I4 and shaft l3 are composed of any insulation material suitable for the purpose in order that arcuate commutator strips 29 through 24, secured in any conventional manner, to disc I2, and their coacting brushes 25 through 29, disposed radially on disc I4, may be insulated from each other and from their respective discs, each of the brushes being slidabiy carried in a metal cup 30 and each cup having a spring 35 disposed therein for yieldably urging the brushes into engagement with the commutator strips individual thereto.

commutator strips 20 through 24 are of progressively greater lengths from the center of disc 12 outwardly and one end of each of the strips lies in a common radius or datum line such that the brushes disengage their commutator strips simultaneously when disc I2 is rotated clockwise from its position as shown in Figure 1 and brushes 25 through 29 disengage their commutator strips progressively or successively in the order named when disc I2 is rotated counter-clockwise from the position shown in Figure 1, the progressive disengagements being spaced according to desired speeds of the engine controlled, as will become more clearly apparent as the description proceeds.

Wires or conductors 36 through 40, connected to brushes 25 through 29, pass through a suitable opening 4| in a cover plate 42 secured to a flange 43 of disc I2 in registered engagement therewith at 44 as by suitable screws 45. Each of commutator strips 20 through 24 is connected as by a suitable conductor 65 to a contact ring 41 carried by disc [2 for rotation therewith. Contact ring 41 slideably engages a similar contact ring 48 secured to shaft I3 whereby the commutator strips are continuously electrically connected to a conductor 49 secured to contact ring 48, a suitable opening 50 being provided in the shaft to permit passage of conductor 49 therethrough.

A reversible direct current motor is employed to impart rotative movement in either direction to disc I2 which, for this purpose, has a gear 52 preferably formed integrally therewith and adapted to be driven by a pinion 53, carried on the motor shaft'54, through a suitable train of gears herein shown to comprise an idler or intermediate gear 55.

An automatic braking system generally designated 56 is employed to releasably lock the motor shaft against rotation while the motor is deenergized, to instantly release the shaft for rotation when the motor is energized, and to instantly lock the shaft against rotation when the motor is de-energized, thereby to prevent overrunning or over-shooting of the motor or slipping of the shaft thereof during deenergization whereby spurious adjustments of the throttle are avoided.

The aforedescribed functions of the braking system are accomplished by means of a brake drum 51 which is secured to the motor shaft 54 for rotation therewith and adapted to be releasably locked against rotation by a brake band 58 having a lining 59 of suitable friction material. The brake band is pivotally secured at one end thereof to the motor case or housing as by a pin 60. This end of the brake band has a radial bore 6| formed therein and adapted slidably to receive a rod 62 having a threaded portion which passes through an opening 63 provided in the free end of brake band 55. Nuts 64 carried by the rod on either side of the free end of the band are employed to adjust variably the compression of a coil spring 65 which is sleeved on rod 62 between a pair of washers B6 and 57 carried thereon and respectively urged by the spring into abutting relation with the fixed end of the brake band and a pin 63 carried by the rod, the nuts being adjusted suificiently to allow for self-adjustment of the brake band to compensate for wearing of the lining whereby the brake band, under power of the spring, serves to irictionally lock the drum. Means are provided, however, for causing movement of rod 62 in a direction to compress the spring as motor 5i is energized, thereby to release the drum and motor shaft for rotation. This means comprises a bell crank Gil which is pivoted on the motor case by means or a pin 10 and which is provided with slotted arms adapted to receive pins ll and I2 respectively carried by rod 62 and a plunger I3 of a solenoid It having a coil I5 which terminates in leads or conductors I6 and 71. By reason of this linkage between plunger I3 and rod 62, the rod is moved in a direction to separate the ends of brake band 58, thereby to release brake system 58, upon movement of the plunger into coil I5 as the coil is energized.

Leads 16 and ll of solenoid I4 are connected respectively to terminals I8 and I9 disposed on terminal box or panel of motor 5i, terminal I9 also being connected by way of a conductor 8i to the negative side of a suitable battery 82. Conductor 49 from throttle control unit I9 and a conductor 83 are connected to a third terminal 84 and a conductor 85 is connected to a fourth terminal 85 provided on the terminal panel, conductors 49, 83 and 85 being adapted to apply positive potential from battery 82 to the terminals individual thereto whereby motor 5! is operated in reverse directions as terminals 84 and 88 are energized selectively in response to conditions more fully to appear as the description proceeds.

Referring now to Figure 2A it will be seen that motor 5| comprises an armature ill carried by shaft 54 ,and a field winding 88 adapted to be reversely connected to the armature and to terminal I9 and terminal 83 or 85 selectively as relays 89 and 90 are energized selectively in accordance with selective application of positive battery potential to either terminal 83 or 85, thereby to reverse the direction of rotation of armature 8! in a well known manner.

The specific manner in which the direction of rotation of motor shaft 54 is accomplished will best be understood by first tracing the circuits which cause the motor shaft to be released for rotation in a counter-clockwise direction and thereafter tracing the circuits which release the shaft and cause it to rotate in a clockwise direction. When positive potential is applied to either conductor 49 or 83, a circuit is completed for operating relay 89 from battery 82 by way of terminal 84, lead or conductor 91, coil of relay 89, and thence by way of conductor 92 through field winding 88 to negative battery potential on terminal I9. As relay 89 operates: a circuit for energizing the armature is completed from positive potential on terminal 84 by way of conductor 9|, brush 93, winding of armature 8?, brush 94, switch 95 or relay 89, and thence by way. of; conductor: Matti negative ipotentlall'onz terminah 19 a circuit? is: completed ion energize ingsithez'fieldt'iwinding from terminaleutbywawofi: conductor SI; switch. 95' of-frelay 8.91;- conductor 9:7; field-winding; 883 andithencetbyew'ay oi' 'coneductor 9-2 to negativezpotential-aom'terminal:19; and: atcircuita -is campleted for energizingtsolez noidz I4 ;.thereby to reieasaa braking system: 55'; from: termin at 81! by way: of: conductor 9 I';' switch 98 ofr. relay 89;. conductor: 91 tot; terminal :1 8; con 1 ductor IS-,acoilflli of solenoid: 1'43;andtthencewby: Way cf: conductors H toi negative potential on! terminal 19?: Whempositive; potential? is: applied? to conductor: 85'; a circuitsisr CDlYlDlGtBdZfiOI-ODBIF atingrrelay, 901mm: positive potential on termi'iial- BE-by way'o'flconductcrr 9.8, Wi1'lding oiirelay fillzand. thenc'ez by" Way? of conductor 92 5150 negatlvezpoe tentia'l' omterminallilt: As relay--9i0.operates: a circuit.- forrenergizirig the armature 8131 br-ushz 93 conductor 91;. switch2 99; of relay 90} and thence byswayioi condncton QZETtOilIBgafiVG potential on terminal I9 a1circuit is completedsfon energizing fieldiwindingmfi from positive potential on terminal i8li-by way ofl'conductorilflr, switch l'lllli ofirelay" 90', conductor; 9.1; V field winding! 8.8; and. thence bywayofi'con'ductor: $1 2 to negative potential ontermihali'IQl';;andia circuitlis completed for energizin-g solenoiwldv by way of" terminal 8H; corrterminal. 1&3 conductor? 16, coil f."ofi solenoid Mg-and tfiencabyrwayi offconductor H to neg-ative potentiali on: terminal "I9. From" the foregoing? it. shouldincw be apparent that: current: from batterw 82 iscaused "to: in the same directionrthrough:fieldawinding flli and' solenoicl Wihd' ing: 1.5 andi in: opposite directions through'the armature when: terminals '84 and 863" and. therefore: relays 89F 'and 90? are energized selectively, thus? satisfying; the conditions necessary to arelease of the armature shaft and rotation: tliereof in either direction.-

Pbsitive potentialfrom batteri 82 is applied by: way" of; a conductor IIII to -the manually set'-- table switch blade I'IZIZ:0Fa:speed control513x103 for the internal combustion engihe to be" con trolled; the switch blad'ehavingahandle portion I Mi. whereby theswitch' blad'e may be rotated manually about a shaft WET-into: engagement with contacts lili' and-Iflfof any-one of a phi--- ralit'y ofspeed positions designated 400 throng-h SOWRIPE and forw-ard -F'and reverse-R.

Conductor" 8-3 from: terminal M of" motor El is connected. to? contact- I UBhbf position" F oncon"- trol box:- I 03 whereby: positive pot'ential on= bat tery 11 2: is applied'to conducton 83 by: Way of" conductor IOI switchblade I02; and thence by way of Contact I llll of positibn': F wlien theswit'ch blade is set ihtb' engagement; therewith;- thuscausing: the motor shaft" to= rotate in aforward" or' counter c'lo'clt'wise direction- Similarly; conductor 85? from -t'ermi'na'l 8-6 of 'motcr 5'I' isconnested to contact- Iill of' position R on--control box I 03' W-1ieieby positlve potentiat from battery is caused to; rotate in: a, reverse or clockwise cli rection. wher'r the swit'cli blade or wiper lilf is set on position R.

Contacts HIB of: positions NW-through HO'Uon control' box I1l3 are connected 'to conductors 36 through 40 I whereby positive potential from battery 82% is applied' to conductor 1 l-lll and" mutorshaft 54 is :causedito rotate-in -a counter clocliwise directicn -when switchblade I02 is set on" any vidediby thetpositions i of" control! box:- I 03;" the relays beingenergized by'means responsive to-:the' tempemturei offthek engine: andi adaptedr to gene crate, or cause to be generated, electro-motive' forces variablysintaccordancewith the temperaturethereofi Any "temperattire-responsive means suitabl'e for thepurpose such; for example; as a 253thermocouple:gen'erally':designated? I23f'm'ay be employed"; the thermocouple comprising two: strips =offi dissimilarmetals I2 4: and I 25? whlch i are" joined' together' at 'l'ilfii-to form: a hot junction adapted tc': be disposed in'i heat transfer "relationfi cwitfi respect tb 'a convenient position on the engine--'sucli; for example, as=.within :-theexhaust manifold orpiper- Strips" In andl 25am further joined-as at -I to fbr-m afcolcl" junction having terminals I 28 and' l 2&f're'spectively a'ssociatewwith strips-u l flfland-i l-25iand adapted to generate' E. M. FFs electroniotive':f6rces) variablysin accordance With the difie'rence's in temperature of the hot andi cold'? junctions; asiswell known in t-heart; Helays I Imithrough: I Hare electric'all y connected 44-); imparallelitovterminalsI 28 and I29 'of tl'ie thermm couple and? accordingly; are adapted to'-be ener gized vafiab'ly as Mi"Fl"s a.regenera-ted bythe thermocouple iniaecordancewithvariations inthe engine'rtemperaturez' An -alternate?"arrangement, Figure 5; for the thermocoupl'e may lie-provided inx'the =-formof a bimetallic 'strip lafl 'orotlier-heat motor sueli; for

eXamp1e;-. an expansible bellbwsh-avinga volatile-fiuid adapt'ed to vary -in volume'in accordance with: variations-amt temperature; the bimetallic element or-othenlieati motor; as tliecase may be, beingadapted' tddfive variabl'ythe wiper I 3 I of asrheostat I32 through a connecting link I33 in accordance with the t'emperature' of theheat 5' source: with: which: tlie bimetallic "element or heat mnturris' associated. Wiper-- I3 'I is arrangedfto engager-selectively a: pluralit'y of contacts I'35 cli's P05861201? theiresistarrce coil I36 of rheosta-t I32 wherebylselected porti-onsof the-ccil may becon- (so nectedi miseries through an: obvious circuit-withabatterrya IBtL -liy W-yof'wi'pep IN, and" Ffs of vaieyingtivalhes caused to appear betweenterminals or leads mama I 3!! in accordance with the: movement; of the heat motorin response to temperaturewariatfons sensed tliereliy, relays I 08" thrciugrhiv lieing 'connecte'd in parallel to leads I 38T and 13 E w lleirtl'iisi alternate arrangement" is employedf Eelaysilm arrd' lllfi" M l and' 'I IZE l'I Fand H53 76" II??? audit-I8; and mfl' and l 21 are adaptedto' control respct lveli th e operation ofswit'ches M0 thrcugl'i I which cvjnnirlse fixed contacts eon-- nectedtir coniihctors 38 through? 41? respectively and inovable-contaets eaell ofwhich is connected" td conductors lm connection with-- terminal 81- on motor Relays I08, III, H4, H1 and I20 are employed to close switches 40 through I44 respectively whereas relays I09, H2, H5, II 8 and |2I are employed thereafter to open the switches individual thereto in a manner hereinafter more clearly to appear.

Relays H0, H3, H6, H9 and I22 control respectively the operation of switches I60 through IE4 which comprise fixed contacts connected respectively to conductors I45 through I49 in connection with contacts I01 of positions 400 through 800 on control box I03 and movable contacts each of which is connected to conductor 85 in connection with terminal 86 on motor 5|, these relays being adapted to close their associated switches when energized to a predetermined value and adapted to open their switches when the energization thereafter declines from such predetermined value, as will become more clearly apparent from a description of the operation of the invention.

Figure 4A illustrates an alternate circuit arrangement for relays I08 and I09 in which each of these relays controls a separate switch I50 and |5I respectively. In accordance with this arrangement operation of relay I08 closes switch I50 and completes a circuit from conductor 36, through switch I50, and thence through normally closed switch |5| to conductor 83. This circuit is opened, however, as relay I09 operates to open switch |5I. Similarly, separate switches may be employed with the other relays adapted to control automatically the application and removal of positive potential on conductor 83.

It may be desirable to provide current of greater magnitude for actuating each of relays I08 through I22. This may be accomplished by interposing between the thermocouple and each of relays I08 through I22, a circuit including a gas thyratron tube I52 of the trigger type as in Figure 6 in which a relay I53, similar to relays I08 through I22, is connected in the plate circuit of the tube in series with a battery I54 and in which the thermocouple operates into the grid circuit of the tube in series opposing with a negative bias battery I55, the grid being coupled to the cathode by a stabilizing circuit element such as a resistor or condenser I55 in the usual manner. According to this arrangement, when the voltage of the thermocouple decreases the nega tive bias of battery I55 to a predetermined value, the tube is caused to conduct or pass current from the plate to the cathode thereof. As the tube conducts, its resistance drops to a low value and permits a large current to flow from battery I54 through the coil of relay I53 thereby to actuate the relay and close switch I51 controlled thereby. Bias batteries of various values may be selected for use with the several relays I 08 through I22 whereby thermocouple voltages of various magnitudes may be required in the tube circuits individual thereto in order to trigger the tubes respectively associated with the several relays.

The various elements of the speed control system having been described, the operation thereof will now be considered, the operation being best understood by a consideration of specific examples thereof. Let it be assumed that it is desired to operate the internal combustion engine or engines at 600 R, P, M. This is accomplished by first setting each control box I03 in its F or R position, whichever is necessary to cause op eration of motor 5| which will set the commutator strips 20 to 24 into engagement with their respective brushes 25 through 29. Each 8 control box is then adjusted to its 600 position which causes motor 5| to operate in a counterclockwise direction by Way of battery 82, conductor |0|, switch blade I02, contact I06 of position 600, conductor 38, brush holder 30 and brush 21, commutator strip 22, conductor 45, rings 41 and 48, conductor 49, terminals 84 and I9 of motor 5i, and thence by way of conductor 8| to the negative side of battery 82. The motor then continues to operate until the foregoing circuit is opened as commutator strip 22 disengages brush 2?. With the engine throttle thus adjusted, the engine is caused to operate at approximately 600 R. P. M. and the temperature thereof rises to a value proportional to the desired speed, as the temperature of the engine increases toward this value, thermocouple I23 develops a progressively increasing E. M. F. (electromotive force) which causes relays I08 through H4 to operate. As relay I I 4 operates a circuit is completed for driving motor 4| further in a counter-clockwise direction, this circuit being traced by way of positive potential on conductor 38, switch I42, and thence by way of conductor 83 to terminal 84. As the motor operates, the throttle is further adjusted and the speed and temperature of the engine is increased until the E. M. F. at the thermocouple increases sufficiently to cause relay M5 to be actuated whereupon switch I42 is opened and the circuit to motor 5| is interrupted. The engine is nOW operating at 600 R. P. M. Should the speed, and consequently the temperature corresponding thereto, rise above this value, relay H5 is caused to operate the close switch I62 whereby a circuit for causing motor 5| to operate in a clockwise direction is completed by way of battery 82, conductor |0|, switch blade Hi2, contact I01 of position 600, conductor I47, switch I62, conductor 85, contacts 86 and I9 of motor 5|, and thence by way of conductor 3| to the negative side of battery 82. The motor then continues to operate in a clockwise direction until the throttle has been cut down sufiiciently to lower the temperature and speed of the engine such that the E. M. F. at the thermocouple becomes insufficient to maintain the operation of relay H5 whereupon switch I62 is opened and operation of the motor 5| ceases and the engine speed is restored to 600 R. P. M. Similarly, in the event that the engine speed becomes less than 600 R. P. M. such that the E. M. F. at the thermocouple is insufiicient to maintain the operation of relay H5, switch I42 again closes to apply posiitive potential on terminal 84 of motor 5|, thus causing the motor to operate counter-clockwise and restore the speed of the engine to 600 R. P. M. If it is desired to operate the engine at 800 R. P. 14., it merely is necessary to adjust the control box to position 800 whereupon motor 5| operates counter-clockwise until commutator strip 24 disengages brush 28, and as the temperature of the engine rises, relays IE through 2| operate to set the engine throttle such that the engine speed conforms to 800 R. P. the operational procedure being substantially the same as described in connection with operation of the engine at 600 R. P. M.

Now if it is desired to operate the engine at 400 R. P. M., the control box I03 is set in the reverse position R to drive motor 5| clockwise until commutator strip 20 engages its coacting brush 25 and thereafter, the control box is set on position 400 whereupon motor 5| is driven counter-clockwise until commutator strip 20 disengages brush 25. With the throttle thus cut down from its ad- :9 justinentr at 800 1R. P.:M.,i the engine temperature decreases until a :circuit :is iag'ain complete'd to motor byway o-fposition-fi460;1conduetor 36,5and switch 40,nwhereuponzthe'motor is iur therdriven counter-clockwise until relay l flfioperatesto open switch 4 5%, I thus providing an adjustment-of the engine throttle adapted to "maintain the engine speed at 400 R. P. M.,- deviations from -thisspeed being adjusted through automatic operation of relays in N38 or 140,- as the :case may -be,-'substantially in the same manner as'iheretofore described in connection with control *of the engine at 3600 and:800 RQPQM.

From theiforegoingit shouldanowbe apparent that -a speed :control system: has been provided which is well adapted to fulfill ithe aforestated objects of the invention. i-More'over, it Will= be apparent that :the invention may Joe employed to advantagein the control of the temperature of-various-types of heat sourcesor devices.

'-While 'the foregoing specificationasetsliorthithe invention in specificl'terms, it is to be'eunderstood that numerousrehanges in: the shape-size and materials may be resorted to withoutdepartingt-from the spiritand scope .of the :invention as :claimed hereinafter.

:Having thus described ourjnvention, .what we claim-as new is:

-1. 'In "a speed control ssystem ifor can internal combustion vengine operating under :a ,constant load" and having a -throttle zfor tcontrollin'g the speed thereof; thecsicombinat-ions f zmanually operativemeansvforiselectively setting the -throttle into any oneofi aiplurality ofpositionsi-adapted .to pro duce speeds vof the ien'gine c-whichconform approximately to .:a plurality :of desired-::speeds thereof, vmeansresponsive -to ithe 4 temperature of the engineand adaptedztoproduce M. Fisproportional to the temperature: thereof ::a :plurality ofelectro -responsive :devices-c-adaptedtto: be zoperated. successively:bysaid ttemperature responsive means asithetemperature of the: engine: increases and at temperatures acorresponding respectively to saididesired' speeds :ofthe renginenandl-means controlled :by :said eelectro-responsive devices :for causing .additional :tadjustments aof the throttle as necessary to bringtthe (speed of the iengine into substantial conformance with avdesiredzspeed thereof.

72. lIna speed: control'system :for 1 an internal combustion engine operating underza constant load and having au-throttle,--for controlling-the speed thereof, the combinations of electromotive means; for adjusting-the zthrottle,--manually'- operativec'means fort-controlling operation oftheeelectromotivemeansand adaptedto cause the.-'electromotivexmeans to set the throttle; selectively-in a plurality 5 of .positions adapted --to r produce ..a plurality of desired :operating speeds 0f the engine, .means responsive to the temperature: of

produce.additional -adiustmentswof the ithrottle ras necessary to bringrtheaspeed of 'the engine into substantial conformance with .a desired speed thereof.

.3. In "a :speed J control :system "cior :aan :internal combustion engine :pperating zunder .sa-sconstant lead aandihaving a ithrottle ior :controlling are speed thereof, thetcombirmtionmf aelectromotlve meansr-forladiustingsthe throttle, means including azsource of power forscausing :therelectromotlve means-i to :set-the throttle selectively in at 4:111- ra'lity'of positions adapted to .iproduceisaziplw rality cof :"desired op'eratinglspeeds of :the engine, manually r operative m'eans rsettabl'e, ss'electively into atplurality of positions :for nitiating ssaid selective operations of' 'the selectromotive-xmeans andrmeans controlled by said selectroeresponsive devices for :e'ausing :isaid ieleetromotive u neans operate to producesadditionalsadjustmentssofI'the throttle =as necessary -to- 'bring hthe speedmfi the engine into substantial conformance with a desir-edaspeed thereof.

lJIn a speed control system f'ior an internal combustion engine 'operating under a rpnstant loadand- 'having a throttle '-"forcontrolling the speed -thereofgthe combination of aithermocouple disposed in *heat transfer -relatiomwith respect to *the -'eng'ine, firs't, *second and third -relays adapt-ed to "be operated 'in -successicn hy 1171-18 thermocouple as the temperature-of ithe-engine rises between 'predetermined -valuespa reversible electric 'motor for adjustingnthe' throttle *of the engine, a first circuit -adapted to be =-'es'tablished as the first-relayoperates for causing said motor to operate '-in a direction to adjust thethrottle towar'd a *position providing a desired *speed "of the engine and-adapted to -be interrupted as-the second relay 'operates, and :a secon'd a'circuit adapted-to beeStebbliShecl as the-third-relay operates for causing -the*'motortOoperate in the opposite direction'to adjust the X throttle toward sa-id position*providin-gsaid'desired speed of the eugine and-adapted -to-be 'interrupted as I the third relayreleases upon-a decrease in theenginetemperature.

*5. In "a "speed ,"GODtI'Ol system for an "internal combustion engine "operating under 'a --constant load" and having- *a throttle "for *contrcllingth-e speed thereof, thecombinationor-athermocouple disposed in heat transfer relationwith respect to the engine; a -"plurality of relays ---adapted "to be; operated variably-by thethermocouple-asthe E. M. Fx'generated 'fthereby' varies in response to changes {in the temperature or the engine, and means controlledby th'e 'relays {for "causingvsuch adjustmentspf thethrottle-a-s'necessary-tomain; tain thetemperature "of ,the engine substantially at'artempera'tm'ewhichisconformstodesiredspeed or the engine.

6. "In ;a"speed control system for 'an "internal combustion -engine operating Tunder "a "constant load and having a throttle -for -controlling "the speed thereof, the "combination Of'ffi reversible electric motor, "driving connections ibetween the motor "and :the throttle whereby the 'throttleu's opened or closed "by the "motor "selectively "as it operates 'in :either direction, brush "and commutator means associated-with said-driving connectio ns, "a *circuit in'cluding sai'd brush 'fand commutator meansrand the motor wherebythe motor may 'b'e 'driventodisengage thebrush arrd "commutator means and open the -"circuit "at a "positien df'the throttle 'corresponding approximately to a desired speed ofthe-engine, -temperature responsive-means disposed in heatttransferarelation rho cthe .zen'gine rand radapted :to generate Efls proportionalto deviationsftrom azpredee terminedtztemperature oftfcheaenginetwhiehworra spouds'ctoiithe idesiredsrspeed :thereof, rand :maans controlledsbyitthe itemperature:n'esponsiveimeans iorseausing::suchiforwardsand:reversennwements 11 of. the motor as necessary to maintain the engine at the desired speed thereof.

'7. In a speed control system for an internal combustion engine operating under a constant load and having a throttle for controlling the speed thereof, the combination of a reversible electric motor, driving connections between the motor and the throttle whereby the throttle is opened or closed by the motor selectively as it operates in either direction, brush and commutator means associated with said driving connections, a circuit including said brush and commutator means and the motor whereby the motor may be driven to disengage the brush and commutator means and open the circuit at a position of the throttle corresponding approximately to a desired speed of the engine, temperature responsive means disposed in heat transfer relation to the engine and adapted to generate E. M. F.s proportional to deviations from a predetermined temperature of the engine which corresponds to the desired speed thereof, a first relay adapted to be operated by said temperature responsive means when the E. M, F. generated thereby is less than that corresponding to said predetermined temperature, a second circuit including said motor and adapted to be closed as the first relay operates to drive the motor in a direction to open the throttle, a second relay adapted to be operated by said temperature responsive means when the E. M. F. generated thereby corresponds to said predetermined temperature and adapted to open said second circuit as the second relay operates, a third relay adaptto be operated by said temperature responsive means when the E. M. F. generated thereby is greater than that corresponding to said predetermined temperature, and a third circuit including said motor and adapted to close as the third relay operates to drive the motor in a direction to close the throttle, said third relay being released to open said third circuit as the temperature of the engine decreases to said predetermined value.

3. In a speed control system for an internal combustion engine operating under a constant load and having a throttle for controlling the speed thereof, the combination of a reversible electric motor, driving connections between the motor and the throttle whereby the throttle is opened or closed by the motor selectively as it operates in either direction, a plurality of commutators of varying lengths carried by the driving connections, a plurality of coaoting brushes for the ccmmutators respectively, manually operative means settable into a plurality of positions for selectively connecting the motor in circuit with each of the commutators and its coaoting brush whereby the motor may be driven to open the throttle variably as each circuit is interrupted by disengagement of the brush and commutator individual thereto to a plurality of different positions, corresponding approximately to a plurality of desired speeds of the engine, a pair of switch s associated with each'of the positions of the manually operative means and adapted to close a circuit to further operate the motor in a direction to open the throttle when one of the pair of switches is closed and adapted to close a circuit to operate the motor in a direction to close the throttle when the other of the pair of switches is closed, and means responsive to deviations in the temperature of the engine from any one of a plurality of predetermined temperatures which correspond to said desired speeds 12 thereof for closing said pairs of switches selectively as the temperature of the engine deviates from a selected predetermined temperature.

9. In a speed control system for an internal combustion engine operating under a constant load and having a throttle for controlling the speed thereof, the combination of a reversible electric motor, driving connections between the motor and the throttle whereby the throttle is opened or closed by the motor selectively as it operates in either direction, a plurality of commutators of varying lengths carried by the driving connections, a plurality of coaoting brushes for the commutators respectively, manually operative means settable into a plurality of positions for selectively connecting the motor in circuit with each of the commutators and its coaoting brush whereby the motor may be driven to open the throttle variably as each circuit is interrupted by disengagement of the brush and commutator individual thereto to a plurality of diiferent positions, corresponding approximately to.a plurality of desired speeds of the engine, a pair of switches associated with each of the positions of the manually operative means and adapted to close a circuit to further operate the motor in a direction to open the throttle when one of the pair of switches is closed and adapted to close a circuit to operate the motor in a direction to close the throttle when the other of the pair of switches is closed, means responsive to the temperature of the engine and adapted to generate a voltage variably in accordance therewith, such a plurality of first, second, and third relays for controlling operation of each pair of said switches, said relays being connected in parallel to said voltage generating means and adapted to be operated successively thereby as the voltage increases, said one of said pair of switches being closed to additionally operate the motor to further open the throttle beyond a selected one of said plurality of approximate adjustments thereof as the first relay operates and said one of said pair of switches being opened as said second relay operates, and said other of said pair of switches being closed to operate the motor in a direction to close the throttle as the third relay operates.

10. In a speed control system for an internal combustion engine operating under a constant load and having a throttle for controlling the speed thereof, the combination of a thermocouple disposed in heat transfer relation with respect to the engine, first, second, and third relays, trigger circuit means including a gas thyratron tube disposed between the thermocouple and each of said relays, each of said trigger circuit means including a voltage source in series opposing with the thermocouple and of such value as to cause the relays to be operated in sequence and at predetermined temperatures as the temperature of the engine increases, said first, second and third relays adapted to be operated in succession by the thermocouple as the temperature of the engine rises between predetermined values, a reversible electric motor for adjusting the throttle of the engine, a first circuit adapted to be established as the first relay operates for causing said motor to operate in a direction to adjust the throttle toward a position providing a desired speed of the engine and adapted to be interrupted as the second relay operates, and a second circuit adapted to be established as the third relay operates for causing the motor to operate in the opposite direction to adjust the 13 throttle toward said position providing said desired speed of the engine and adapted to be interrupted as the third relay releases upon a decrease in the engine temperature.

11. In a speed control system for an internal combustion engine operating under a constant load and having a throttle for controlling the speed thereof, the combination of a reversible electric motor, driving connections between the motor and the throttle whereby the throttle is opened or closed by the motor selectively as it operates in either direction, means for locking the motor against rotation when the motor is de energized and adapted to instantly release the motor for operation so the motor is energized, brush and commutator means associated with said driving connections, a circuit including said brush and commutator means and the motor whereby the motor may be driven to disengage the brush and commutator means and open the circuit at a position of the throttle corresponding approximately to a desired speed of the en- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,838,408 King et a1. Dec. 29, 1931 2,272,188 Danielson Feb. 10, 1942 2,275,317 Ryder Mar. 3, 1942 2,314,937 Hannon Mar. 30, 1943 

